The settlement announced Tuesday by the Justice Department and the Environmental Protection Agency includes a $970,000 fine, which will be split with the state of Kansas. It also requires the Coffeyville refinery to put in $4.25 million in upgraded pollution controls and $6.5 million in operating costs.

Regulators say the improvements are designed to benefit the environment and protect the health of residents living near the facility.

Sulfur dioxide and nitrogen oxide emitted from refineries can cause health problems and contribute to acid rain, smog and haze.

The agreement includes more stringent emission limits and more aggressive leak detection and repair practices.

The government alleged the company made modifications at the refinery that increased emissions without first obtaining permits and installing required pollution control equipment. It also alleged the company failed to timely notify state and local emergency responders of releases of hydrogen sulfide and sulfur dioxide from the facility.

It is the 30th settlement under an EPA initiative to improve compliance and reduce air pollution. With the Kansas settlement, 107 refineries operating in 32 states and territories — compromising more than 90 percent of the nation's refining capacity — are under a judicially enforceable agreement to reduce pollution, the Justice Department said.

The Coffeyville refinery can refine more than 115,000 barrels of crude oil daily into gasoline, diesel fuels and propane.